I could be just sitting and watching TV when all of a sudden I'd get very tired and nauseous, my heart ache would increase and my body muscles would hurt where I'd have to drag myself to bed. This happens when I'm at school or work. I just get lucky when I am at home. Right now I'm on break from school and get very good sleep although it seems like I can't get enough of it. During last semester I've had no days off and worked and went to school everyday. My job is very stressful and I have to stand the whole day. What could be causing my sudden fatigue

Has it occurred to you to see a doctor and get a complete checkup?

That's something nobody online can do for you.